Camera for vehicle vision system with enhanced heat removal

ABSTRACT

A camera module for a vehicular vision system includes a lens barrel having a plurality of optical elements accommodated therein, a front camera housing portion that accommodates at least one printed circuit board therein, and a rear camera housing portion mated with the front camera housing. The imager is optically aligned with an optical axis of the optical elements. A heat transfer element is disposed between and in thermal conductive contact with a thermoelectric device and the printed circuit board. Circuitry of the camera module is electrically connected to the imager and the thermoelectric device and is electrically connected to electrical connecting elements that electrically connect to a wire harness of a vehicle when the camera module is disposed at the vehicle. The thermoelectric device is electrically powered to draw heat from the imager printed circuit board to the rear camera housing portion.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the filing benefits of U.S. provisionalapplication Ser. No. 62/575,651, filed Oct. 23, 2017, which is herebyincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for avehicle and, more particularly, to a vehicle vision system that utilizesone or more cameras at a vehicle.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties. Various cameras have beenproposed for such imaging systems, including cameras of the typesdescribed in U.S. Pat. No. 7,965,336 and U.S. Publication No.US-2009-0244361, which are hereby incorporated herein by reference intheir entireties.

SUMMARY OF THE INVENTION

The present invention provides a vision system or imaging system for avehicle that utilizes one or more cameras to capture image datarepresentative of images exterior of the vehicle. The camera or cameramodule comprises an imager and a circuit board (or circuit boards) and alens at a lens barrel. A front camera housing portion is configured toreceive an imager printed circuit board therein, with the imager printedcircuit board disposed at the lens barrel with the imager opticallyaligned with an optical axis of optical elements of the lens. A rearcamera housing portion is mated with a rear portion of the front camerahousing so as to encase and seal the imager printed circuit board in thecamera module. A thermoelectric device is disposed at the rear camerahousing portion, and a heat transfer element is disposed between and inthermal conductive contact with the thermoelectric device and the imagerprinted circuit board. The thermoelectric device is electrically poweredto draw heat from the imager printed circuit board to the rear camerahousing portion. The thermoelectric device may be operable responsive toa temperature sensor disposed in the camera module. Circuitry of thecamera module is electrically connected to the imager and thethermoelectric device and is electrically connected to electricalconnecting elements that are configured to electrically connect to awire harness of the vehicle.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates cameras in accordance with the present invention; and

FIG. 2 is a sectional view of a camera module in accordance with thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide display, such as a rearviewdisplay or a top down or bird's eye or surround view display or thelike.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes at least one exterior facing imaging sensor or camera,such as a rearward facing imaging sensor or camera 14 a (and the systemmay optionally include multiple exterior facing imaging sensors orcameras, such as a forward facing camera 14 b at the front (or at thewindshield) of the vehicle, and a sideward/rearward facing camera 14 c,14 d at respective sides of the vehicle), which captures images exteriorof the vehicle, with the camera having a lens for focusing images at oronto an imaging array or imaging plane or imager of the camera (FIG. 1).Optionally, a forward viewing camera may be disposed at the windshieldof the vehicle and view through the windshield and forward of thevehicle, such as for a machine vision system (such as for traffic signrecognition, headlamp control, pedestrian detection, collisionavoidance, lane marker detection and/or the like). The vision system 12includes a control or electronic control unit (ECU) or processor 18 thatis operable to process image data captured by the camera or cameras andmay detect objects or the like and/or provide displayed images at adisplay device 16 for viewing by the driver of the vehicle (althoughshown in FIG. 1 as being part of or incorporated in or at an interiorrearview mirror assembly 20 of the vehicle, the control and/or thedisplay device may be disposed elsewhere at or in the vehicle). The datatransfer or signal communication from the camera to the ECU may compriseany suitable data or communication link, such as a vehicle network busor the like of the equipped vehicle.

The control unit may comprise or may be part of an autonomous vehiclecontrol system, whereby the cameras capture image data that is processedfor use in autonomously controlling the vehicle. Such high resolutionautonomous vehicle cameras require exceptional image quality for machinevision. Image quality degradation occurs from sensor noise at elevatedtemperatures. Automotive industry sensor suppliers see this occurring tosome degree at temperatures as low as 45 degrees C.

High-resolution and automotive cameras take steps to optimize heattransfer between the image sensor or imager and external heatdissipating features. Many such cameras are expected to operate inambient temperatures as high as around 85 degrees C. so can rarelyachieve sensor junction temperatures below around 100 degrees C. Imagedegradation at these temperatures may be substantial and limits machinevision capabilities.

The autonomous vehicle camera of the present invention includes activecooling. As shown in FIG. 2, a thermoelectric cooler (TEC), or Peltierelement, is used to substantially cool the image sensor to a desiredtemperature. The camera thus comprises the first automotive camera withan actively cooled image sensor. The camera includes temperature sensorswithin the camera that are used to control power to the TEC as neededfor cooling effect. For example, responsive to the sensed temperaturebeing above a threshold level, power to the TEC may be provided orincreased or modulated or controlled to provide more cooling. The systemmay continuously or episodically sense or monitor the camera temperatureand may continuously or episodically adjust the power supplied to theTEC to provide the desired cooling effect. The sensor and control forsensing temperature and controlling or powering the TEC may be part ofthe camera module itself, such as part of the circuitry disposed on oneor more circuit boards in the camera module.

As also shown in FIG. 2, the rear cover of the camera will be used as a“heat sink” and can have cooling fins or pins. The TEC is disposed orcaptured between the rear cover or rear housing portion and a copper oraluminum “cold finger” or element that directs or transfers the heatfrom the image sensor to the TEC. Optionally, for space efficiency, acentralized heat removal system (the cold finger in FIG. 2) may extendthrough holes in additional PCBs to provide the heat transfer pathcentrally from the image sensor to the TEC at the rear housing portion.

Thus, and such as shown in FIG. 2, the camera module of the presentinvention includes a lens barrel and camera upper or front housingportion, with the imager disposed at or near the lens barrel and focusedand aligned with the optical elements of the lens barrel. The rearhousing portion includes an electrically powered thermoelectric coolerthat is in contact with a heat transfer element or cold finger thatextends from the TEC to the imager circuit board. Optionally, a thermalinterface material may be disposed between the imager circuit board andthe heat transfer element to enhance heat transfer from the rear of theimager circuit board to the heat transfer element. The thermal interfacematerial may comprise any suitable thermally conductive material, suchas, for example, thermally conductive paste, epoxy, film or tape or thelike, which establishes a thermally conductive connection between theend of the heat transfer element and the printed circuit board.

The heat transfer element is formed to be disposed over and at leastpartially around the TEC and is attached to the rear housing portion viafasteners or screws, which may be tightened to clamp the heat transferelement to and around the TEC to provide and maintain contact betweenthe heat transfer element and the TEC. Thermal insulators may beprovided at the screws. Optionally, for example, a desiccant sheet withadhesive backing may be disposed between the heat transfer element andthe rear housing portion. Optionally, a heat spreader, such as one madefrom graphite (such as a graphite sheet or layer or film, or such asanother suitable heat spreading or heat diffusing sheet or layer orfilm, such as, for example, a graphene sheet or layer or film or thelike), may be disposed between the heat transfer element and the rearhousing portion to enhance the rear cover sink ability.

In the illustrated embodiment, the camera module includes two printedcircuit boards (in addition to the imager PCB) that include circuitryassociated with the imager and camera. The heat transfer elementprotrudes generally centrally aligned holes or apertures in the two PCBsand terminates at the rear of the imager PCB, such that the heattransfer element thermally conductively connects at the rear of theimager PCB to draw or conduct or transfer heat generated by the imager(during operation of the camera) away from the imager PCB to the TEC andrear cover or housing portion. Optionally, the heat transfer element maycontact one or both of the other PCBs to draw heat from them as well.Optionally, the heat transfer element may engage a rear side of anothercircuit board (and not engage the imager PCB) to draw heat fromcircuitry or components that are disposed on the other circuit board(such that heat generated by an image processor of the other circuitboard is drawn away from the image processor and toward the rear of thecamera). Circuitry of the PCBs and of the camera module (including theimage processor and TEC or circuitry associated with the TEC) iselectrically connected to the imager and is electrically connected toelectrical connecting elements that are configured to electricallyconnect to a wire harness of the vehicle when the camera module isdisposed at the vehicle.

As shown in FIG. 2, the heat transfer element is in thermal conductivecontact with the TEC and with the rear housing or cover and the heatsink, and extends therefrom into the cavity of the camera module. Theend of the heat transfer element that is distal from the TEC and therear housing is in thermal contact with the imager PCB (at the rear oropposite side of the imager PCB from where the imager is disposed). Theheat transfer element protrudes through an aperture or hole through oneor more other PCBs, which are centrally aligned with the axis of thecamera module and lens assembly. The desiccant sheet and/or heatspreader may be disposed at the interior surface of the rear housingportion and between the rear housing portion and the heat transferelement (which may be fastened to the rear housing portion via fastenersor the like) to spread the heat conducted by the heat transfer element(drawn from the PCB(s) via operation of the TEC) over the rear housingportion and heat sink to enhance cooling of the camera module duringoperation.

Also, the image sensor PCB is directly adhesively bonded at the frontcamera housing or lens or lens barrel. To eliminate all sources ofmovement between the lens and image sensor, the imager or its printedcircuit board is bonded directly to the lens structure or lens barrel,such as via a suitable quick-cure adhesive (see FIG. 2). The bondingadhesive also acts as the pliable assembly element or member between theoptics and the imager or imaging sensor for the focus and alignmentsteps (and then cures to a cured state that retains the imager PCB andimager relative to the lens barrel and lens). For example, the adhesiveand focus and alignment steps may utilize aspects of the cameras andprocesses described in U.S. Pat. Nos. 8,542,451 and 9,277,104, which arehereby incorporated herein by reference in their entireties.

The camera module may utilize aspects of the cameras and connectorsdescribed in U.S. Pat. Nos. 9,621,769; 9,596,387; 9,277,104; 9,077,098;8,994,878; 8,542,451 and/or 7,965,336, and/or U.S. Publication Nos.US-2009-0244361; US-2013-0242099; US-2014-0373345; US-2015-0124098;US-2015-0222795; US-2015-0327398; US-2016-0243987; US-2016-0268716;US-2016-0286103; US-2016-0037028; US-2017-0054881; US-2017-0133811;US-2017-0201661; US-2017-0280034; US-2017-0295306; US-2017-0302829and/or US-2018-0098033, and/or U.S. patent applications, Ser. No.16/165,170, filed Oct. 19, 2018, now U.S. Pat. No. 10,750,064, and/orSer. No. 16/165,253, filed Oct. 19, 2018, now, U.S. Pat. No. 10,678,018,which are hereby incorporated herein by reference in their entireties.

The camera or sensor may comprise any suitable camera or sensor.Optionally, the camera may comprise a “smart camera” that includes theimaging sensor array and associated circuitry and image processingcircuitry and electrical connectors and the like as part of a cameramodule, such as by utilizing aspects of the vision systems described inInternational Publication Nos. WO 2013/081984 and/or WO 2013/081985,which are hereby incorporated herein by reference in their entireties.

The system includes an image processor operable to process image datacaptured by the camera or cameras, such as for detecting objects orother vehicles or pedestrians or the like in the field of view of one ormore of the cameras. For example, the image processor may comprise animage processing chip selected from the EYEQ™ family of image processingchips (for example, an EYEQ3™, EYEQ4™ or EYEQ5™ image processing chip)available from Mobileye Vision Technologies Ltd. of Jerusalem, Israel,and may include object detection software (such as the types describedin U.S. Pat. Nos. 7,855,755; 7,720,580 and/or 7,038,577, which arehereby incorporated herein by reference in their entireties), and mayanalyze image data to detect vehicles and/or other objects. Responsiveto such image processing, and when an object or other vehicle isdetected, the system may generate an alert to the driver of the vehicleand/or may generate an overlay at the displayed image to highlight orenhance display of the detected object or vehicle, in order to enhancethe driver's awareness of the detected object or vehicle or hazardouscondition during a driving maneuver of the equipped vehicle.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 9,233,641;9,146,898; 9,174,574; 9,090,234; 9,077,098; 8,818,042; 8,886,401;9,077,962; 9,068,390; 9,140,789; 9,092,986; 9,205,776; 8,917,169;8,694,224; 7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331;6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202;6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452;6,822,563; 6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935;6,636,258; 7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229;7,301,466; 7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287;5,929,786 and/or 5,786,772, and/or U.S. Publication Nos.US-2014-0340510; US-2014-0313339; US-2014-0347486; US-2014-0320658;US-2014-0336876; US-2014-0307095; US-2014-0327774; US-2014-0327772;US-2014-0320636; US-2014-0293057; US-2014-0309884; US-2014-0226012;US-2014-0293042; US-2014-0218535; US-2014-0218535; US-2014-0247354;US-2014-0247355; US-2014-0247352; US-2014-0232869; US-2014-0211009;US-2014-0160276; US-2014-0168437; US-2014-0168415; US-2014-0160291;US-2014-0152825; US-2014-0139676; US-2014-0138140; US-2014-0104426;US-2014-0098229; US-2014-0085472; US-2014-0067206; US-2014-0049646;US-2014-0052340; US-2014-0025240; US-2014-0028852; US-2014-005907;US-2013-0314503; US-2013-0298866; US-2013-0222593; US-2013-0300869;US-2013-0278769; US-2013-0258077; US-2013-0258077; US-2013-0242099;US-2013-0215271; US-2013-0141578 and/or US-2013-0002873, which are allhereby incorporated herein by reference in their entireties. The systemmay communicate with other communication systems via any suitable means,such as by utilizing aspects of the systems described in InternationalPublication Nos. WO/2010/144900; WO 2013/043661 and/or WO 2013/081985,and/or U.S. Pat. No. 9,126,525, which are hereby incorporated herein byreference in their entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

The invention claimed is:
 1. A camera module for a vehicular visionsystem, said camera module comprising: a lens barrel having a pluralityof optical elements accommodated therein; a front camera housingportion; at least one printed circuit board accommodated in said cameramodule; an imager disposed at a front side of said at least one printedcircuit board; an image processor disposed at said at least one printedcircuit board; wherein, with said at least one printed circuit boardaccommodated in said front camera housing portion, said imager isoptically aligned with an optical axis of said optical elements; whereinsaid at least one printed circuit board comprises an imager printedcircuit board having said imager disposed thereat and attached at saidfront camera housing portion; wherein said at least one printed circuitboard comprises a processor printed circuit board having said imageprocessor disposed thereat and disposed in said camera module and spacedfrom and electrically connected to circuitry of said imager printedcircuit board; a rear camera housing portion; a thermoelectric devicedisposed at said rear camera housing portion; a heat transfer elementdisposed between and in thermal conductive contact with saidthermoelectric device and a rear side of said at least one printedcircuit board; wherein said heat transfer element extends through anaperture of said processor printed circuit board; wherein said rearcamera housing portion is mated with said front camera housing portionso as to encase said at least one printed circuit board and saidthermoelectric device in said camera module; wherein circuitry of saidcamera module is electrically connected to said imager, said imageprocessor and said thermoelectric device and is electrically connectedto electrical connecting elements that are configured to electricallyconnect to a wire harness of a vehicle when said camera module isdisposed at the vehicle; and wherein said thermoelectric device, withsaid electrical connecting elements electrically connected to the wireharness of the vehicle, is electrically powered to draw heat from saidat least one printed circuit board to said rear camera housing portionvia said heat transfer element.
 2. The camera module of claim 1, whereinsaid camera module is configured to be disposed at an exterior portionof the vehicle so as to have a field of view exterior of the vehicle. 3.The camera module of claim 1, wherein said rear camera housing portioncomprises a heat sink.
 4. The camera module of claim 1, wherein saidheat transfer element is attached at a rear structure of said rearcamera housing portion and is held in contact with said thermoelectricdevice at said rear structure of said rear camera housing portion. 5.The camera module of claim 4, wherein said heat transfer element isattached at said rear structure of said rear camera housing portion viaa plurality of fasteners.
 6. The camera module of claim 1, comprising atemperature sensor disposed in said camera module, wherein saidthermoelectric device operates responsive to said temperature sensor. 7.The camera module of claim 1, comprising a thermal interface materialdisposed at the rear side of said at least one printed circuit board andbetween and in thermal conductive contact with the rear side of said atleast one printed circuit board and said heat transfer element.
 8. Acamera module for a vehicular vision system, said camera modulecomprising: a lens barrel having a plurality of optical elementsaccommodated therein; a front camera housing portion; at least oneprinted circuit board accommodated in said camera module; an imagerdisposed at a front side of said at least one printed circuit board; animage processor disposed at said at least one printed circuit board;wherein, with said at least one printed circuit board accommodated insaid front camera housing portion, said imager is optically aligned withan optical axis of said optical elements; a rear camera housing portion;a thermoelectric device disposed at said rear camera housing portion; aheat transfer element disposed between and in thermal conductive contactwith said thermoelectric device and a rear side of said at least oneprinted circuit board; wherein said rear camera housing portion is matedwith said front camera housing portion so as to encase said at least oneprinted circuit board and said thermoelectric device in said cameramodule; wherein said heat transfer element is attached at a rearstructure of said rear camera housing portion and is held in contactwith said thermoelectric device at said rear structure of said rearcamera housing portion; a desiccant sheet disposed between said rearcamera housing portion and said rear structure where said rear camerahousing portion is attached at said rear structure; wherein circuitry ofsaid camera module is electrically connected to said imager, said imageprocessor and said thermoelectric device and is electrically connectedto electrical connecting elements that are configured to electricallyconnect to a wire harness of a vehicle when said camera module isdisposed at the vehicle; and wherein said thermoelectric device, withsaid electrical connecting elements electrically connected to the wireharness of the vehicle, is electrically powered to draw heat from saidat least one printed circuit board to said rear camera housing portionvia said heat transfer element.
 9. The camera module of claim 8,comprising a heat spreading material disposed between said desiccantsheet and said rear structure of said rear camera housing portion. 10.The camera module of claim 8, wherein said at least one printed circuitboard comprises an imager printed circuit board having said imagerdisposed thereat and attached at said front camera housing portion. 11.The camera module of claim 10, wherein said at least one printed circuitboard comprises a processor printed circuit board having said imageprocessor disposed thereat and disposed in said camera module and spacedfrom and electrically connected to circuitry of said imager printedcircuit board.
 12. A camera module for a vehicular vision system, saidcamera module comprising: a lens barrel having a plurality of opticalelements accommodated therein; a front camera housing portion; an imagerprinted circuit board accommodated in said camera module; an imagerdisposed at a front side of said imager printed circuit board; wherein,with said imager printed circuit board accommodated in said front camerahousing portion, said imager is optically aligned with an optical axisof said optical elements; a processor printed circuit board having animage processor disposed thereat and disposed in said camera module andspaced from and electrically connected to circuitry of said imagerprinted circuit board; a rear camera housing portion; a thermoelectricdevice disposed at said rear camera housing portion; a heat transferelement disposed between and in thermal conductive contact with saidthermoelectric device and a rear side of said imager printed circuitboard; wherein said heat transfer element extends through an aperture ofsaid processor printed circuit board; wherein said rear camera housingportion is mated with said front camera housing portion so as to encasesaid imager printed circuit board and said thermoelectric device in saidcamera module; wherein circuitry of said camera module is electricallyconnected to said imager, said image processor and said thermoelectricdevice and is electrically connected to electrical connecting elementsthat are configured to electrically connect to a wire harness of avehicle when said camera module is disposed at the vehicle; wherein saidthermoelectric device, with said electrical connecting elementselectrically connected to the wire harness of the vehicle, iselectrically powered to draw heat from said imager printed circuit boardto said rear camera housing portion via said heat transfer element; andwherein said camera module is configured to be disposed at an exteriorportion of the vehicle so as to have a field of view exterior of thevehicle.
 13. The camera module of claim 12, wherein said heat transferelement is attached at a rear structure of said rear camera housingportion and is held in contact with said thermoelectric device at saidrear structure of said rear camera housing portion.
 14. The cameramodule of claim 12, comprising a temperature sensor disposed in saidcamera module, wherein said thermoelectric device operates responsive tosaid temperature sensor.
 15. The camera module of claim 12, comprising athermal interface material disposed at a rear side of said imagerprinted circuit board and between and in thermal conductive contact withthe rear side of said imager printed circuit board and said heattransfer element.
 16. A camera module for a vehicular vision system,said camera module comprising: a lens barrel having a plurality ofoptical elements accommodated therein; a front camera housing portion;at least two printed circuit boards accommodated in said camera module;wherein said at least two printed circuit boards comprises an imagerprinted circuit board attached at said front camera housing portion, andwherein said at least two printed circuit boards comprises a processorprinted circuit board disposed in said camera module and spaced from andelectrically connected to circuitry of said imager printed circuitboard; an imager disposed at a front side of said imager printed circuitboard; an image processor disposed at said processor printed circuitboard; wherein, with said imager printed circuit board accommodated insaid front camera housing portion, said imager is optically aligned withan optical axis of said optical elements; a rear camera housing portion;a thermoelectric device disposed at said rear camera housing portion; aheat transfer element disposed between and in thermal conductive contactwith said thermoelectric device and a rear side of one printed circuitboard of said at least two printed circuit boards; wherein said heattransfer element extends through an aperture of at least one otherprinted circuit board of said at least two printed circuit boards;wherein said heat transfer element is attached at a rear structure ofsaid rear camera housing portion and is held in contact with saidthermoelectric device at said rear structure of said rear camera housingportion; wherein said rear camera housing portion is mated with saidfront camera housing portion so as to encase said at least two printedcircuit boards and said thermoelectric device in said camera module;wherein circuitry of said camera module is electrically connected tosaid imager, said image processor and said thermoelectric device and iselectrically connected to electrical connecting elements that areconfigured to electrically connect to a wire harness of a vehicle whensaid camera module is disposed at the vehicle; and wherein saidthermoelectric device, with said electrical connecting elementselectrically connected to the wire harness of the vehicle, iselectrically powered to draw heat from said at least two printed circuitboards to said rear camera housing portion via said heat transferelement.
 17. The camera module of claim 16, comprising a temperaturesensor disposed in said camera module, wherein said thermoelectricdevice operates responsive to said temperature sensor.
 18. The cameramodule of claim 16, wherein said camera module comprises a heatspreading material disposed between said heat transfer element and saidrear structure of said rear camera housing portion.
 19. The cameramodule of claim 16, wherein said camera module comprises a desiccantsheet disposed between said rear camera housing portion and said rearstructure where said rear camera housing portion is attached at saidrear structure.
 20. The camera module of claim 16, wherein the apertureis through said processor printed circuit board.